That might be interesting to explore. But I think they've more or less run out of speedsters: Barry, Wally, Jesse, Eobard, Zoom, Jay, Black Flash, Savitar have all been used and Johnny Quick doesn't exist apparently. Impulse maybe? I assume time isn't linear in the speed force (then again maybe it should be I guess...that's what motion is..things moving through space and time linearly)

Max Mercury? XS? Walter West? Did Wally's kids have speed? I think they had different powers.